SEEING BY WIRE.

Sun (Christchurch), Volume I, Issue 133, 11 July 1914, Page 5

SEEING BY WIRE.

PICTURES ON THE TELEGRAPH.

Dr Archibald M. Low, a young London scientist, claims to have discovered a means by which a wire' can be made to act as a telescope. This, at least, is a rough idea of what does. For a number of years scientists have been able to transmit photographs over a telegraph wire. The principle of this is a peculiar property of the element, selenium. An electric current passing through selenium varies with the amount of light falling on the selenium.

. Dr Low's apparatus • consists of a I transmitter and a receiver connected by wires. The transmitter consists essentially of a screen divided into a large number of small squares, each being a selenium "cell." This screen is contained in a box. In front of it is a lens. The arrangement is like that in a camera screen taking the place of the photographic plate. The lens throws an image of any object before it upon the screen. Different parts of this image vary in light and shade, so that the light falling on the squares of the screen varies in intensity. These squares are brought into electrical connection by wire with the receiving apparatus. As the light falling on the squares varies so do the electrical currents vary. These currents actuate electro-magnets, which in their turn work shutters through which a light shines. The amount of opening of the shutter depends on the strength of the current and therefore on the intensity of the light falling on the corresponding square of the receiving screen. How it Works. Thus, a candle flame would give a bright image on certain squares of the screen, and the corresponding shutters in the receiver would open widely, allowing light to pass through freely. And a person looking through at the receiver would see an image of the candle flame.

Suppose the candle is moved. The image moves across the transmitting

■.'••■■;. '-•. AtSW screen and a corresponding mov'ettient is seen in the receiving screen jJsaWhis indicates how the apparatus wortojfl In practice only the' I one row of squares in the transmitting screen are sent to the receiver at a time. But the currents from the different rows are sent in exceedingly swift succession. Actually, therefore, only one row of squares in the receiving screen is illuminated at a time. But the rows are illuminated in turn so quickly that\ to an observer it seems as if the whole of the image on the receiving screen is seen at the same time. This is really an application of the principle of the kinematograph, in which a series' of slightly varying pictures blend into one as they * are successively flashed before the eye. Dr Low, who has done much Government, research work, demonstrated his invention to a " Daily Mail'' representative, when apparently it, worked, successfully over a distance of 15 feet. He states that it has been worked over a distance of four miles, and declares that there is no reason why, in future,, a man sitting in London should not see and speak (by telephone) with a friend in Glasgow. The invention is called the Televista.

Dr Low, who has worked on the invention for four years, believes that it may be possible to apply the Poulsen. wireless system to his invention and so enable a passenger in a liner to see events that are taking place in London.